Windmoller Holscher

Werner Josef Zimmermann

Hartmut Upmeier

Gerhard Winkler

Helmut Helbig

Ferdinand Loning

In a film blowing plant comprising an extruder for the melt, a film blowhead, calibrating means for the blown tubular film, oscillatory take-off means for the film and a coiler for the flattened film, the output of the plant is set to an optimum figure by a process computer controlling the width and thickness of the film. The height of the line of solidification of the film above the blowhead is measured and, in response to a departure of this height from a given desired value, the output of the extruder is increased or reduced as the case may be.

Method and apparatus for optimizing the output of a blown film extruder

Cooling apparatus for tubular plastics film made by a film blowhead has provision for air cooling and for replacement of the internal cooling air through a central aperture in the blowhead. The cooling apparatus comprises superposed cooling air supply rings having outlet apertures facing the inside of the film and apertures extending axially through the air supply rings for the passage of the cooling air from the lower into the higher air supply rings and radial apertures for withdrawing the cooling air that is blown out of the outlet apertures between the air supply rings. The air supply rings consist of superposed cylindrical rings interconnected by tubular webs that pass through the rings and form radial apertures, the rings being supported on one another at least by their inner ring portions and bounding an annular passage between each other.

Cooling apparatus for air cooling tubular plastics film made by a film

In a blowhead for producing tubular film from thermoplastic material flowing from an extruder, a central supply conduit branches into a plurality of radial distributing passages having their axes in substantially one plane. Each distributing passage extends into an axial passage portion that is parallel to the supply conduit and that opens into a distributing helix. Inlet and outlet tubes for cooling air are provided between the axial distributing passage portions.

Film blowhead for producing tubular film

A rotary blowhead for making tubular plastics film and comprising interior and exterior air cooling means is adapted to be centrally fed with plastics material from a stationary extruder and is connected to stationary air fans by means of segmented air distributing means.

Rotary film blowhead for making tubular films of thermoplastic material

In a blow-head for producing tubular film from thermoplastic molten material and comrising a housing with a central supply conduit for the molten material and distributing passages radiating from the supply conduit to a respective distributing helix of an insert member, means for internally cooling the blown film comprise concentric air inlet and outlet passages extending axially of the housing and each connected to at least one inlet tube and one outlet tube, respectively, the tubes being disposed between adjacent said radiating distributing passages and extending to the exterior of the housing.

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Lengerich of Westphalia, Germany

Werner Josef Zimmermann